The case against the tax on sugar-sweetened beverages is rife with contradictions.

The House Health Care Committee approved the tax earlier this week in the belief that a 1-cent-per-ounce tax would be an important step in the battle against obesity.

But opponents include an influential grocers group and other businesses that stand to lose if Vermonters buy less soda and other sweetened drinks. Opponents also include Gov. Peter Shumlin, who has shown he is able to say contradictory things almost at the same moment.

Shumlin said he did not believe a tax on sugary drinks would be effective in changing people’s behavior. Then in almost the same breath he said he feared the tax would cause Vermonters to drive to New Hampshire to buy their soda. But driving to New Hampshire is a change in behavior. And if you don’t happen to live close to the New Hampshire line, it is conceivable the tax could cause another change: It could discourage you from buying the drink at all.

That is what supporters of the tax believe it will do, especially among kids, for whom soda is a clear and present health threat, and also among low-income Vermonters. They point to the effectiveness of the tax on tobacco in causing a major decline in tobacco use.

Representatives of business argue that the tax would hurt business, causing a decline in sales. At the same time, they argue that the tax will not be effective in causing a decline in sales because it will be spread over a distributor’s many products and will not be felt by consumers. Which is it? Will the tax hurt or won’t it? And if it won’t be felt, wouldn’t that be a good way to raise more than $20 million?

The industry is fighting this tax in a big way because it is the opening salvo in what could be an important war in the fight to free Americans from the allure of foods that harm us.

Mark Bittman, the New York Times food writer, has been scathing about the industrial food business, which he charges with purveying poison and using politics to discourage criticism or even scientific discussion. Sugary drinks, especially, act like poison, particularly as they affect children. They have no nutritional value. They contain such a high concentration of sugar that they can upset a person’s metabolic and hormonal balance, leading to obesity, which causes heart disease and cancer, among many other ills.

Shumlin argues that the tax on sugary drinks is regressive because it would affect poor people most severely. But according to the Vermont Low Income Advocacy Council, that effect will mostly be good because it will discourage poor people from buying so much soda. It is in the interest of poor people that soda be priced out of their budget. By levying a tax by the ounce, it will also have the benefit of discouraging the purchase of larger drinks.

It is natural to resist the demands of people who think they know what’s better for you. If you have a predilection for a nice cold Coke, it’s annoying for the nanny state to chide you that you shouldn’t indulge.

But long ago our state and nation assumed a role in promoting public health. We police the food and drug industry against impurities and phony marketing. We require safety of auto manufacturers. Notably, we have taken on the tobacco industry, which was proven to have mounted a campaign of lies and manipulation to sell a product that was designed to be addictive and was known to be lethal. These are all measures that a civilized nation takes to protect its citizens from industries that profit from the sale of products that do harm.

We are waking up to the harm of high fructose corn syrup, which is evident in the widening girth of Americans and the ill health that is a consequence. That the food industry is fighting this tax in Vermont with such vehemence is a sign of the good it could do. It will cost the industry business. That is the point. Vermonters need to drink less soda, and a tax is one way of helping them do so.